A Correlation Coefficient is a measurement of the relationship between two variables.  A positive correlation means that as one variable increases, the second variable increases too.  A negative correlation means that as one variable increases, the second variable decreases, or as one variable decreases, the second variable increases.  Positive and negative correlations exists in nature, science, business, as well as a variety of other fields.  Please watch the following video for a graphical explanation of the correlation coefficient:

find an example of each of the following and cite your source.

      two variables with a positive correlation

      two variables with a negative correlation